/*
 * Copyright (C) 2008 ZXing authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.yiguantong.police.qrCode.utils.camera;

import android.content.Context;
import android.graphics.ImageFormat;
import android.graphics.Point;
import android.graphics.Rect;
import android.hardware.Camera;
import android.hardware.Camera.Parameters;
import android.os.Build;
import android.os.Handler;
import android.util.DisplayMetrics;
import android.view.SurfaceHolder;

import java.io.IOException;
import java.util.List;

/**
 * This object wraps the Camera service object and expects to be the only one
 * talking to it. The implementation encapsulates the steps needed to take
 * preview-sized images, which are used for both preview and decoding.
 * 
 * @author dswitkin@google.com (Daniel Switkin)
 */
public final class CameraManager {

    /**
     * 定义一个静态的cameraManager
     */
    private static CameraManager cameraManager;

    private Parameters parameter;

    /**
     * 获取构建版本
     */
    static final int SDK_INT; // Later we can use Build.VERSION.SDK_INT
    static {
        int sdkInt;
        try {
            sdkInt = Build.VERSION.SDK_INT;
        } catch (NumberFormatException nfe) {
            // Just to be safe
            sdkInt = 10000;
        }
        SDK_INT = sdkInt;
    }

    /**
     * 定义相机配置管理器
     */
    private final CameraConfigurationManager configManager;

    /**
     * 定义相机
     */
    private Camera camera;

    private Rect framingRect;

    private Rect framingRectInPreview;

    private boolean initialized;

    private boolean previewing;

    /**
     * 定义是否是一次性回调，如果为true的话就是拍一下就停了，再想拍要重新定义拍照的surface
     */
    private final boolean useOneShotPreviewCallback;

    /**
     * Preview frames are delivered here, which we pass on to the registered
     * handler. Make sure to clear the handler so it will only receive one
     * message.
     */
    private final PreviewCallback previewCallback;

    private Context mContext;

    /**
     * Autofocus callbacks arrive here, and are dispatched to the Handler which
     * requested them.
     */
    private final AutoFocusCallback autoFocusCallback;

    /**
     * Initializes this static object with the Context of the calling Activity.
     * 
     * @param context
     *            The Activity which wants to use the camera.
     */
    public static void init(Context context) {
        if (cameraManager == null) {
            cameraManager = new CameraManager(context);
        }
    }

    /**
     * Gets the CameraManager singleton instance. 单例模式
     * 
     * @return A reference to the CameraManager singleton.
     */
    public static CameraManager get() {
        return cameraManager;
    }

    private CameraManager(Context context) {

        this.mContext = context;
        this.configManager = new CameraConfigurationManager(context);

        // Camera.setOneShotPreviewCallback() has a race condition in Cupcake,
        // so we use the older
        // Camera.setPreviewCallback() on 1.5 and earlier. For Donut and later,
        // we need to use
        // the more efficient one shot callback, as the older one can swamp the
        // system and cause it
        // to run out of memory. We can't use SDK_INT because it was introduced
        // in the Donut SDK.
        // useOneShotPreviewCallback = Integer.parseInt(Build.VERSION.SDK) >
        // Build.VERSION_CODES.CUPCAKE;3=Cupcake
        useOneShotPreviewCallback = Build.VERSION.SDK_INT > 3;

        previewCallback = new PreviewCallback(configManager, useOneShotPreviewCallback);
        autoFocusCallback = new AutoFocusCallback();
    }

    /**
     * Opens the camera driver and initializes the hardware parameters. 打开相机
     * 
     * @param holder
     *            The surface object which the camera will draw preview frames
     *            into.
     * @throws IOException
     *             Indicates the camera driver failed to open.
     */
    public void openDriver(SurfaceHolder holder) throws IOException {
        if (camera == null) {
            camera = Camera.open();
            if (camera == null) {
                throw new IOException();
            }
            camera.setPreviewDisplay(holder);

            if (!initialized) {
                initialized = true;
                configManager.initFromCameraParameters(camera);
            }
            configManager.setDesiredCameraParameters(camera);
            // FlashlightManager.enableFlashlight();
        }
    }

    /**
     * Closes the camera driver if still in use. 关闭相机
     */
    public void closeDriver() {
        if (camera != null) {
            // FlashlightManager.disableFlashlight();
            camera.release();
            camera = null;
        }
    }

    /**
     * Asks the camera hardware to begin drawing preview frames to the screen.
     * 相机准备
     */
    public void startPreview() {
        if (camera != null && !previewing) {
            camera.startPreview();
            previewing = true;
        }
    }

    /**
     * Tells the camera to stop drawing preview frames. 相机暂停
     */
    public void stopPreview() {
        if (camera != null && previewing) {
            if (!useOneShotPreviewCallback) {
                camera.setPreviewCallback(null);
            }
            camera.stopPreview();
            previewCallback.setHandler(null, 0);
            autoFocusCallback.setHandler(null, 0);
            previewing = false;
        }
    }

    /**
     * A single preview frame will be returned to the handler supplied. The data
     * will arrive as byte[] in the message.obj field, with width and height
     * encoded as message.arg1 and message.arg2, respectively.
     * 
     * @param handler
     *            The handler to send the message to.
     * @param message
     *            The what field of the message to be sent.
     */
    public void requestPreviewFrame(Handler handler, int message) {
        if (camera != null && previewing) {
            previewCallback.setHandler(handler, message);
            if (useOneShotPreviewCallback) {
                camera.setOneShotPreviewCallback(previewCallback);
            } else {
                camera.setPreviewCallback(previewCallback);
            }
        }
    }

    /**
     * Asks the camera hardware to perform an autofocus.
     * 
     * @param handler
     *            The Handler to notify when the autofocus completes.
     * @param message
     *            The message to deliver.
     */
    public void requestAutoFocus(Handler handler, int message) {
        if (camera != null && previewing) {
            /**
             * 重新设置handler
             */
            autoFocusCallback.setHandler(handler, message);
            /**
             * 让相机自动聚焦
             */
            camera.autoFocus(autoFocusCallback);
        }
    }

    /**
     * Calculates the framing rect which the UI should draw to show the user
     * where to place the barcode. This target helps with alignment as well as
     * forces the user to hold the device far enough away to ensure the image
     * will be in focus.
     * 
     * @return The rectangle to draw on screen in window coordinates.
     */
    public Rect getFramingRect() {
        /**
         * 获得屏幕的大小
         */
        Point screenResolution = configManager.getScreenResolution();
        if (framingRect == null) {
            if (camera == null) {
                return null;
            }

            if (screenResolution == null) {
                return null;
            }

            /* 扫描框修改 */
            DisplayMetrics metrics = mContext.getResources().getDisplayMetrics();

            // 我们可以通过修改下面width height 里0.8 1.0参数 来改变高和宽
            int width = (int) (metrics.widthPixels * 0.7);
            int height = (int) (width * 1.0);

            int leftOffset = (screenResolution.x - width) / 2;
            int topOffset = (screenResolution.y - height) / 3;
            framingRect = new Rect(leftOffset, topOffset, leftOffset + width, topOffset + height);
        }
        return framingRect;
    }

    /**
     * Like {@link #getFramingRect} but coordinates are in terms of the preview
     * frame, not UI / screen.
     */
    public Rect getFramingRectInPreview() {
        if (framingRectInPreview == null) {
            Rect rect = new Rect(getFramingRect());
            Point cameraResolution = configManager.getCameraResolution();
            Point screenResolution = configManager.getScreenResolution();
            // rect.left = rect.left * cameraResolution.x / screenResolution.x;
            // rect.right = rect.right * cameraResolution.x /
            // screenResolution.x;
            // rect.top = rect.top * cameraResolution.y / screenResolution.y;
            // rect.bottom = rect.bottom * cameraResolution.y /
            // screenResolution.y;
            rect.left = rect.left * cameraResolution.y / screenResolution.x;
            rect.right = rect.right * cameraResolution.y / screenResolution.x;
            rect.top = rect.top * cameraResolution.x / screenResolution.y;
            rect.bottom = rect.bottom * cameraResolution.x / screenResolution.y;
            framingRectInPreview = rect;
        }
        return framingRectInPreview;
    }

    /**
     * A factory method to build the appropriate LuminanceSource object based on
     * the format of the preview buffers, as described by Camera.Parameters.
     * 
     * @param data
     *            A preview frame.
     * @param width
     *            The width of the image.
     * @param height
     *            The height of the image.
     * @return A PlanarYUVLuminanceSource instance.
     */
    public PlanarYUVLuminanceSource buildLuminanceSource(byte[] data, int width, int height) {
        Rect rect = getFramingRectInPreview();
        int previewFormat = configManager.getPreviewFormat();
        String previewFormatString = configManager.getPreviewFormatString();
        switch (previewFormat) {
        // This is the standard Android format which all devices are
        // REQUIRED to support.
        // In theory, it's the only one we should ever care about.
        case ImageFormat.NV21:
            // This format has never been seen in the wild, but is
            // compatible as we only care
            // about the Y channel, so allow it.
        case ImageFormat.NV16:
            return new PlanarYUVLuminanceSource(data, width, height, rect.left, rect.top,
                            rect.width(), rect.height());
        default:
            // The Samsung Moment incorrectly uses this variant instead of
            // the 'sp' version.
            // Fortunately, it too has all the Y data up front, so we can
            // read it.
            if ("yuv420p".equals(previewFormatString)) {
                return new PlanarYUVLuminanceSource(data, width, height, rect.left, rect.top,
                                rect.width(), rect.height());
            }
        }
        throw new IllegalArgumentException("Unsupported picture format: " + previewFormat + '/'
                        + previewFormatString);
    }

    public void openLight() {
        if (camera != null) {
            parameter = camera.getParameters();
            if (parameter == null) {
                return;
            }
            List<String> flashModes = parameter.getSupportedFlashModes();
            if (flashModes == null) {
                return;
            }
            String flashMode = parameter.getFlashMode();
            if (!Parameters.FLASH_MODE_TORCH.equals(flashMode)) {
                if (flashModes.contains(Parameters.FLASH_MODE_TORCH)) {
                    parameter.setFlashMode(Parameters.FLASH_MODE_TORCH);
                    camera.setParameters(parameter);
                }
            }
            // parameter.setFlashMode(Parameters.FLASH_MODE_TORCH);
            // camera.setParameters(parameter);
        }
    }

    public void offLight() {
        if (camera != null) {
            parameter = camera.getParameters();
            if (parameter == null) {
                return;
            }
            List<String> flashModes = parameter.getSupportedFlashModes();
            if (flashModes == null) {
                return;
            }
            String flashMode = parameter.getFlashMode();
            if (!Parameters.FLASH_MODE_OFF.equals(flashMode)) {
                if (flashModes.contains(Parameters.FLASH_MODE_OFF)) {
                    parameter.setFlashMode(Parameters.FLASH_MODE_OFF);
                    camera.setParameters(parameter);
                }
            }
        }
    }

}
